In many circumstances and for many reasons, it is often beneficial to capture and draw together two or more pieces of tissue of a patient. The location of the tissue and the circumstances of the need to draw the pieces of tissue together have long resulted in a variety of different devices and methods for drawing the tissue together. Devices such as bandages, both self-adhesive and otherwise, clamps and stitches have been used to capture pieces of tissue and draw them together. Once tissue is drawn together, the natural healing abilities of the body may then allow the pieces of tissue to grow together, over time sealing a gap between the pieces of tissue such that the device is no longer needed. Alternatively, the pieces of tissue may be held together by the device indefinitely, or for a particular period of time.
But, dependent on the location of the tissue, certain devices and methods may be impractical to utilize. For instance, while stitches may lend themselves well to readily accessible patient tissue, such as skin and muscle tissue, relatively inaccessible tissue, such as that found in the organs of the patient, may be impractical to capture and draw together using stitches. As such, the use of stitches to treat a defect in a patient's heart may tend require a traumatic open heart procedure, and even then, because the interior of the heart still may not be readily accessible, the treatment of a defect inside the heart may still not be attainable with stitches. Thus, a common device and method for drawing together patient tissue may not be applicable for all situations, particularly those involving a defect in organs of the patient such as the heart.
One relatively common defect in the heart of newborn children, which may also be present in older children and in adults, is a patent foramen ovale (“PFO”). During the gestation of a fetus in the womb, blood is oxygenated not by the undeveloped lungs of the fetus, but rather by the placenta of the mother. However, the heart of the fetus nevertheless pumps the blood through the cardiovascular system and receives the blood from the cardiovascular system. As such, in order to avoid the undeveloped lungs of the fetus, various vessels and bypasses exist that operate only during gestation that divert the blood from the lungs. At birth these bypasses typically close and circulation occurs by way of the lungs as with a normally developed adult.
An opening between the right atrium and the left atrium called the foramen ovale is open during gestation to prevent transfer of blood from the right ventricle of the heart to the lungs during gestation. Upon birth, the child's inherent circulation creates pressure within the atrium which causes a flap of tissue to close over the foramen ovale. As the child matures, the flap of tissue develops into a permanent closure. However, in some children the flap of tissue does not close, either in whole or in part, over the entire foramen ovale, creating a patent foramen ovale. The continued existence of the foramen ovale results in continued diversion from the lungs of at least some of the child's blood, reducing the flow of oxygenated blood through the child's system, and potentially leading to serious complications to the health of the child.
It is recognized that although PFO may occur most prominently in children and, in particular, relatively newborn children, that the PFO may also occur or be present in older children and in adults.
Other cardiac defects are known to exist beyond patent foramen ovales. For instance, atrial-septal defects (“ASD”) and ventricular-septal defects (“VSD”) likewise sometimes occur and may be detrimental to the health of the person, e.g., a child. Historically, open heart surgery had been required to fix such defects. But open heart surgery carries with it serious and well-known and recognized risks to the well-being of the person, in addition to being expensive and a considerable burden on hospital resources.
Closure devices for treating heart defects, such as patent foramen ovales, have been developed.
U.S. Pat. No. 6,776,784, Ginn, Clip Apparatus For Closing Septal Defects and Methods of Use, (Core Medical, Inc.) discloses a device for closing a septal defect, such as a patent foramen ovale, includes a clip formed from a superelastic material that is inserted into a septum wall of a heart. The clip is advanced through a patient's vasculature, e.g., within a delivery apparatus, until the clip is disposed within a first chamber adjacent the septal defect. Tines of the clip are directed through a flap of tissue of the septal defect until the tines of the clip are disposed within a second opposing chamber. The clip then transforms into its relaxed state, wherein the tines of the clip engage with a surface of the second chamber, thereby substantially closing the septal opening.
U.S. Patent Application Publication No. US2007/0060858, Sogard et al, Defect Occlusion Apparatus, System and Method, discloses occluding a multiplicity of parallel membranes, such as found in a patent foramen ovale. The methods, apparatus, and systems include the use of a positioning device that can be seated on the limbus of the septum secundum. The positioning device includes a piercing member that can pierce the septum secundum and septum primum. The positioning device also includes a fastening member that can engage the septum secundum and septum primum to fasten the tissues and thereby occlude a patent foramen ovale.
U.S. Pat. No. 7,220,265, Chanduszko et al, Patent Foramen Ovale (PFO) Closure Method and Device, (NMT Medical, Inc.) discloses methods and devices for closing two overlapping layers of tissue in a mammalian heart, such as a patent foramen ovale. The closure devices may take a number of different forms and may be retrievable. In some embodiments, the closure devices may be delivered with a catheter capable of puncturing mammalian tissue. In some embodiments, a spring-like bioabsorbable polymer material are used, in one such embodiment as a “grappling hook”, to embed in and draw together the pieces of tissue. In another embodiment, a suture is delivered, and an anchor forms a pre-determined shape and engages the septum secundum, closing the patent foramen ovale.